1. Technical Field
The present invention relates to the improvement of an electret and an electrostatic induction conversion device comprising the same.
2. Related Art
Conventionally, electrostatic induction conversion devices such as a power generator or a microphone using an electret in which an electric charge is injected in an insulating material have been proposed. For example, a fluorine-containing polymer described in Patent Document 1 as below can be used as a material of the electret.    Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 4-189880
However, when the conventional fluorine-containing polymer is used, the density of charges to be injected into an electret cannot be increased and the surface potential is insufficient. This causes a disadvantage that the conversion efficiency between electric energy and kinetic energy in the electrostatic induction conversion device using the electret cannot be improved.